PROJECT SUMMARY Carotid Artery Stenting (CAS) using embolic protection represents the current standard of care for patients with carotid artery stenosis considered at high risk for carotid endarterectomy. Distal filter devices are the most widely used protection devices, but these must be navigated through plaque prior to deployment, presenting a significant embolic risk. Strong evidence indicates proximal protection devices, especially using flow reversal, improve outcomes compared to distal protection devices. Currently in the US, there exists no minimally invasive, transfemoral system for flow reversal CAS; the only currently marketed flow reversal system (Silk Road) requires a surgical cutdown of the common carotid artery. Silk Road has the advantage of short, large bore catheter systems that maximize flow reversal. Previous transfemoral flow reversal products (Parodi, Gore), since removed from the market, required complex, dual balloon systems that prolonged procedures and added risk. In this proposal, we will develop and validate the Femoral Flow Reversal Access for Carotid Artery Stenting (FFRACAS) device, to provide the endovascular therapy community with a novel tool that does not require invasive surgery and will speed carotid artery stenting while facilitating a flow reversal. The central innovation of our device is aimed at minimizing the system?s outer diameter and maximizing its inner diameter balloon occlusion device that functions both as a long arterial introducer sheath and an occlusion balloon, with a relatively small OD and profoundly increased ID. As a result, the flow reversal capability of our system, even without need for a dual balloon approach, is as good or better than Silk Road. These key features in our proposed device will facilitate a better, safer and faster alternative to CAS. Our specific aims are 1) to develop and perform in vitro pilot testing of our FFRACAS device, and 2) to perform iterative in vivo testing and validation of the FFRACAS device in swine carotid artery model. Our primary objective is for the FFRACAS device to 1) provide ease of percutaneous placement, 2) achieve atraumatic cessation of antegrade flow, and 3) achieve in vivo rates of reversed flow equal to or greater than that of the Silk Road device (the best standard for treatment via reverse flow) at each stage of the CAS procedure. Completion of these goals in Phase 1 will pave the way toward design validation and development of an Investigational New Device trial in Phase 2. We anticipate that the use of our device will create better, minimally-invasive curative solutions to CAS.